Venogram
A venogram is a specialized test done under X-ray that shows the blood flow through the veins. During the procedure, the doctor inserts a thin tube called a catheter into the femoral vein in the groin and advances it through the vein. Your doctor then injects a special fluid called contrast media, or contrast dye, through the catheter into your blood stream.
The contrast dye allows the x-ray to show real time moving images of the blood flow through the veins. The doctor uses these images to identify the precise location of any narrowing / blockages in the veins. Based on the findings of this test, your doctor is able to determine if further treatment is needed.